Extruder feeding assembly and extruder apparatus incorporating it

Abstract

Disclosed is an extruding apparatus and relative feeding assembly, including hopper unit in correspondence of an extruder-feeding area, wherein an extrusion screw having a first rotation axis and a drive roller having a second rotation axis are arranged at a distance each other so that a gap for raw material feeding is defined between the screw and the drive roller, wherein the drive roller has a substantially conical surface with respect to its own rotation axis, the conical surface having a taper vertex facing toward a progression direction of the extrusion screw.

1 . Feeding assembly of an extruder, comprising hopper means in correspondence of an extruder-feeding area, wherein an extrusion screw ( 10 ) having a first rotation axis (X-X′) and a drive roller ( 20 ) having a second rotation axis (Y-Y′) are arranged at a distance each other so that a gap for raw material feeding is defined between a flight envelope of said screw ( 10 ) and said drive roller ( 20 ), characterised in that
 said drive roller ( 20 ) has a substantially smooth conical surface with respect to its own rotation axis (Y-Y′), said conical surface having a taper vertex facing toward a progression direction of said extrusion screw ( 10 ). 
 
     
     
         2 . Feeding assembly as in  claim 1 , wherein the taper of said substantially conical surface is comprised between about 0.1° and about 30°, preferably between about 0.5° and about 5°. 
     
     
         3 . Feeding assembly as in  claim 1 , wherein the taper of said substantially conical surface is such that the difference between the minimum and maximum peripheral linear velocity on said surface, upon rotation about said second rotation axis (Y-Y′), is comprised between 0.1% and 50%. 
     
     
         4 . Feeding assembly as in  claim 1 , wherein said substantially conical surface is determined by a curved generating line. 
     
     
         5 . Apparatus for the extrusion of rubber-based or silicon-based material, comprising at least an extrusion screw ( 10 ) and a drive roller ( 20 ), mounted side by side in a feeding area of semi-processed material, wherein said feeding area is provided with a feeding assembly as in  claim 1 . 
     
     
         6 . Extrusion apparatus as in  claim 5 , wherein said second rotation axis (Y-Y′) of the drive roller ( 20 ) is substantially parallel to said first rotation axis (X-X′) of said screw ( 10 ). 
     
     
         7 . Extrusion apparatus as in  claim 5 , wherein said second rotation axis (Y-Y′) is converging with respect to the first rotation axis (X-X′) of said screw ( 10 ) with an angle smaller than 30°. 
     
     
         8 . Extrusion apparatus as in  claim 5 , wherein said drive roller ( 20 ) is driven into rotation by a drive independent from the motor driving the extrusion screw ( 10 ).